def abc(a,b,c=50):
    print(a,b,c)
abc(10,20)
# 可变长参数
def bcd(a,b,*args,**kwargs):
    print(a,b,args,kwargs)
bcd(10,20)
bcd(10,20,5,5,5)
bcd(10,20,c=20,d=30)
# 计算不定长数列的和
def get_sum(*args):
    sum = 0
    for i in args:
        sum += i
    return sum
print(get_sum(1,2,3,4,5,6,7,8,9))